JPH04365307A - Solid electrolytic capacitor - Google Patents

Abstract

PURPOSE:To contract a distance between a capacitor element and an anodic lead terminal, for making the capacitor element voluminous in a solid electrolytic capacitor. CONSTITUTION:A capacitor element 1 has a structure, wherein its semiconductor layer 5 is formed only on the peripheral surface of an anodic body 3, which excludes an anodic lead 5 or the surface of the anodic lead 5 being drawn out. Since the semiconductor layer is absent on the anodic lead, there is no possibility of an anodic lead terminal 7 contacting with the semiconductor layer 5. Therefore, the distance between the capacitor element and the anodic lead terminal can be contracted. As a result, the capacitor element can be lengthened, and an electrolytic capacitor having a high volumetric efficiency is obtained.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid electrolytic capacitor, and more particularly to the structure of a lead-out portion of a valve metal anode lead embedded in a valve metal body.

0002

[Prior Art] Conventionally, this type of solid electrolytic capacitor is shown in Fig. 3.
As shown in (a), a dielectric layer 4, a semiconductor layer 5, and a cathode layer 6 are sequentially formed on a valve metal anode body 3 from which an anode lead 2 is led out.The cathode layer 6 of a capacitor element 1 is connected to a cathode lead terminal 8.
using conductive adhesive 9 and connecting the anode lead 2 to
After connecting it to the anode lead terminal 7, cover it with a mold and attach it to the anode lead terminal 7.
Cathode lead terminals 7 and 8 are molded along exterior resin 10. As shown in FIG. 4, the semiconductor layer 5 of this capacitor element has a structure in which the manganese nitrate solution 12 creeps up onto the anode lead 2, so that it is formed on the anode lead 2 and its lead-out surface.

Furthermore, as shown in FIG. 3(b), there is also a structure in which a semiconductor adhesion prevention resin 11 is provided at the lead-out portion of the anode lead 2 in order to prevent manganese nitrate from creeping up during the decomposition process.

0004

[Problems to be Solved by the Invention] In this conventional molded exterior chip type solid electrolytic capacitor, when the semiconductor layer 5 is attached to the anode lead 2 shown in FIG. If 5 contacts, a short circuit will occur.

On the other hand, when the semiconductor layer adhesion prevention resin 11 shown in FIG. Strength may drop significantly and open defects may occur. Therefore, both require a certain distance or more between the lead-out portion of the anode lead 2 and the anode lead terminal 7.

[0006] Therefore, the proportion of the capacitor element 1 in the length direction of the solid electrolytic capacitor is small, resulting in a disadvantage that the volumetric efficiency is low.

An object of the present invention is to provide a chip-shaped solid electrolytic capacitor that can increase the length of a capacitor element in the longitudinal direction of the solid electrolytic capacitor and has high volumetric efficiency.

[0008]

[Means for Solving the Problems] The solid electrolytic capacitor of the present invention has a capacitor element in which a dielectric layer, a semiconductor layer, and a cathode layer are sequentially formed on a valve-action metal anode body from which an anode lead is led out, in which the semiconductor layer is formed. It has a structure in which it is formed only on the circumferential surface of the anode body, excluding the anode lead or its lead-out surface.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained with reference to the drawings. FIG. 1 is a side sectional view of one embodiment of the present invention.

First, the anode lead 2 embedded in the anode body 3
A resin mixed with a fluororesin, a cellulose resin, and a surfactant is applied to the lead-out portion of the anode body 3, and a dielectric layer 4 and a semiconductor layer 5 are formed on the surface of the anode body 3. After that, the anode body 3 is immersed in a surfactant solution. The resin at the lead-out portion of the anode lead 2 is removed by applying ultrasonic waves.

After that, the cathode layer 6 of the capacitor element 1 with the cathode layer 6 formed thereon was connected to the cathode lead terminal 8 and the anode lead 2 to the anode lead terminal 7 using a conductive adhesive 9, and the capacitor element 1 was molded and packaged. Rear, positive/cathode lead terminal 8.
9 is bent along the exterior resin 10 to obtain a molded exterior chip type solid electrolytic capacitor.

[0012] By the above means, the shape has a width of 1.25 mm.
, a molded exterior chip type solid electrolytic capacitor with a length of 2.0 mm and a height of 1.2 mm was fabricated. Since the semiconductor layer 5 was not present on the anode lead 2, the distance between the capacitor element 1 and the anode lead terminal 7 was changed from the conventional one. As a result, the capacitor element 1 could be made longer, and a capacitance 1.4 times that of the conventional product could be obtained.

FIG. 2 is a side sectional view of another embodiment of the invention. A dielectric layer 4 and a semiconductor layer 5 are formed on the surface of the anode body 3 in which the anode lead 2 is embedded, and then a cathode layer 6 is formed using a conductive paste using epoxy resin, and then soaked in a nitric acid solution for 1 minute. The anode lead 2 and the semiconductor layer on its lead-out surface are dissolved and removed by immersion for 10 minutes.

Thereafter, the cathode layer 6 is connected to the cathode lead terminal 8 and the anode lead 2 is connected to the anode lead terminal 7 using conductive adhesive 9, and the anode lead terminal 8 and the anode lead terminal 8 are connected to each other. 9 is bent along the exterior resin 10 to obtain a molded exterior chip type solid electrolytic capacitor.

This embodiment has the advantage that the semiconductor layer on the lead-out surface of the anode lead 2 can be removed uniformly, improving dimensional accuracy.

[0016]

As explained above, the present invention makes it possible to shorten the distance between the capacitor element 1 and the anode lead terminal by not forming a semiconductor layer on the anode lead or its lead-out surface. The length of the capacitor element in the longitudinal direction can be increased, and a chip-shaped solid electrolytic capacitor with high volumetric efficiency can be obtained.

[Brief explanation of drawings]

FIG. 1 is a side sectional view of one embodiment of the invention.

FIG. 2 is a side sectional view of another embodiment of the invention.

[Figure 3] A side sectional view of a conventional solid electrolytic capacitor, (a)
The normal structure (b) is one in which a semiconductor layer adhesion prevention resin is provided at the anode lead lead-out portion.

FIG. 4 is a schematic diagram showing a situation where a manganese nitrate solution creeps up onto the anode lead.

[Explanation of symbols]

1 Capacitor element 2 Anode lead 3 Valve action metal anode body 4 Dielectric layer 5 Semiconductor layer 6 Cathode layer 7 Anode lead terminal 8 Cathode lead terminal 9 Conductive adhesive 10 Exterior resin 11 Resin for preventing semiconductor adhesion 12 Manganese nitrate solution

Claims (1)

[Claims] Claim 1: A capacitor element in which a dielectric layer, a semiconductor layer, and a cathode layer are sequentially formed on a valve-action metal anode body from which an anode lead is led, in which the semiconductor layer is formed on the anode lead or the anode body except on the lead-out surface thereof. A solid electrolytic capacitor characterized by being formed only on the peripheral surface.